The present invention relates generally to snowshoes, and more particularly to a snowshoe having novel means for limiting pivotal articulation of a binding support plate relative to the snowshoe frame.
Snowshoes have traditionally been used as a convenient means to traverse relatively deep snow. With the increased interest in outdoor activities, such as hiking and the like, the use of snowshoes in the backcountry has grown significantly. More recently, there has been increased interest in running or jogging on snowshoes, including the holding of races with the runners wearing snowshoes. Racing events have special requirements. For example, each runner's snowshoes must meet certain minimum size standards in width and length, generally 8" wide and 25" in length. Further, in running on snowshoes it is highly desirable that any articulated movement between the snowshoe and the runner's foot or boot be controlled so as to prevent flopping of the snowshoe relative to the user's foot as the snowshoe is lifted from the surface of the snow during running or jogging.
Conventional snowshoes have a frame which forms the perimeter of the snowshoe and is generally made of wood or a tubular lightweight metal such as aluminum. The perimeter frame may be reinforced by transverse cross bars and has floatation means secured thereto, such as a traditional webbing laced tight to the frame. Early snowshoe designs provided for relatively fixed attachment of the snowshoe to the user's foot so that very little articulation was allowed between the snowshoe and the user's boot. More recent snowshoe designs employ a hinge rod which is fixed transversely to the frame to underlie the ball of the user's foot. The hinge rod pivotally supports a relatively rigid foot or claw plate. A binding to receive the user's shoe or boot is secured to the top of the claw plate and one or more cleats or calks are preferably fixed to the bottom of the claw plate to provide better gripping when traversing packed snow or ice. A tubular bearing, such as a plastic sleeve or bushing, is preferably coaxial on the hinge rod to minimize friction between the hinge rod and its pivotal connection to the claw plate. A snowshoe of this general construction is disclosed in U.S. Pat. No. 3,802,100 which is incorporated herein by reference.
While snowshoes of the aforedescribed type have performed satisfactorily in backcountry snowshoeing, they lack optimum performance characteristics desired in snowshoes used in jogging or running on packed snow. In backcountry snowshoeing in relatively deep powder, it is important that vertical lift of the snowshoe be minimized since snow generally accumulates on top of the snowshoe and thereby requires greater expenditure of energy to lift the snowshoe with each step taken. Thus, snowshoes intended for backcountry snowshoeing generally enable the user's foot to freely pivot about the hinge rod so that minimal lifting of the snowshoe takes place upon pivotal movement of the user's foot during a forward step.
Running or jogging on snowshoes of the aforedescribed type, particularly on packed snow, is generally made more difficult by the relative ease with which the claw plate pivots about the hinge rod on a snowshoe intended for backcountry use. As the jogger or runner takes each step, the foot initially pivots forwardly followed by lifting of the snowshoe so that the forward and tail ends lift off the surface of the snow. With prior snowshoes, as the snowshoe is lifted from the snow surface, the toe end may slap against the user's shin with a resultant bruise and soreness. To prevent such action, prior snowshoes have employed an elastic strap having one end fixed to the frame of the snowshoe generally adjacent its tail end and having an opposite end secured to either the trailing end of the claw plate or adapted for connection to the user's boot or ankle. The strap limits angular rotation of the snowshoe frame relative to the claw plate to an included angle of approximately 45.degree.. This technique, however, has a significant disadvantage in that the elastic strap stretches and causes the frame and floatation webbing to snap or slap against the user's heel when the snowshoe lifts off the snow. The resulting slapping noise is annoying in addition to imparting an undesirable upward force on the user's foot.